Subject: Re: ascii dump for tcpdump (was Re: truss-like command for netbsd)
To: Robert Elz <kre@munnari.OZ.AU>
From: Dustin Sallings <dustin@spy.net>
List: current-users
Date: 10/13/1998 11:13:50
On Tue, 13 Oct 1998, Robert Elz wrote:
# Once you get past the protocol headers and into the data, you're
# generally going to be much better off with something designed for
# debugging the particular protocol of concern, than just looking at ascii
# flying past.
Have you ever used snoop for Solaris? This is an example of me
telnetting to a machine (snoop -v port telnet):
ETHER: ----- Ether Header -----
ETHER:
ETHER: Packet 21 arrived at 10:55:34.55
ETHER: Packet size = 61 bytes
ETHER: Destination = 8:0:69:7:91:b2, Silicon Graphics
ETHER: Source = 8:0:20:71:85:27, Sun
ETHER: Ethertype = 0800 (IP)
ETHER:
IP: ----- IP Header -----
IP:
IP: Version = 4
IP: Header length = 20 bytes
IP: Type of service = 0x00
IP: xxx. .... = 0 (precedence)
IP: ...0 .... = normal delay
IP: .... 0... = normal throughput
IP: .... .0.. = normal reliability
IP: Total length = 47 bytes
IP: Identification = 15172
IP: Flags = 0x4
IP: .1.. .... = do not fragment
IP: ..0. .... = last fragment
IP: Fragment offset = 0 bytes
IP: Time to live = 255 seconds/hops
IP: Protocol = 6 (TCP)
IP: Header checksum = fe2c
IP: Source address = a.x.y.z, server.domain.com
IP: Destination address = w.x.y.z, host.domain.com
IP: No options
IP:
TCP: ----- TCP Header -----
TCP:
TCP: Source port = 23
TCP: Destination port = 7523
TCP: Sequence number = 3151110952
TCP: Acknowledgement number = 1630222130
TCP: Data offset = 20 bytes
TCP: Flags = 0x18
TCP: ..0. .... = No urgent pointer
TCP: ...1 .... = Acknowledgement
TCP: .... 1... = Push
TCP: .... .0.. = No reset
TCP: .... ..0. = No Syn
TCP: .... ...0 = No Fin
TCP: Window = 8760
TCP: Checksum = 0x548f
TCP: Urgent pointer = 0
TCP: No options
TCP:
TELNET: ----- TELNET: -----
TELNET:
TELNET: "login: "
TELNET:
That's the most verbose way to run it, there are many variations.
This tool has been essential in tracking down many server and network
problems in the past.
--
SA, beyond.com My girlfriend asked me which one I like better.
pub 1024/3CAE01D5 1994/11/03 Dustin Sallings <dustin@spy.net>
| Key fingerprint = 87 02 57 08 02 D0 DA D6 C8 0F 3E 65 51 98 D8 BE
L_______________________ I hope the answer won't upset her. ____________